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Population Facts

Population facts and facts about populations, from the Random Facts shelf.

9 facts on this shelf

Blue whale massacre crustaceans

The blue whale, the worlds largest animal at 110 feet according to guiness world records eat krill, which are shrimp-like crustaceans only about an inch-and-a-half long.


Pick on somebody your own size? Not whales! An adult whale might slaughter 40 million, or 4-6 tons of these little creatures in one day!!

Amazingly, the krill population persists, but you have to assume this perpetual atrocity affects the krills ability to develop a stable society.

The rule of 72

The rule of 72 is used to find the number of years it takes to double your money at a given interest rate.

(72/[interest rate]) = years until a principle doubles



So, how long will it take to double your money at eight percent interest? Divide 8 into 72 and you get 9 years.



If you collect 7% on your savings in a little over 10 years the amount will be double what it is today.


The rule of 72 also means that you can determine the time
it takes for a population to double if it is growing at a steady rate by solving this function:

(72/[rate of growth]) = years for population to double

U.S. population, and how many people do you have to poll?

When a poll tells us a candidate for president of the United States is favored by ___% of the population, they tell us it has a "margin of error" of +-__% .

For example, August 6, 2008, CBS poll on the president of the United States put John McCain with 39% of the vote and Barrak Obama 45% of the vote, with a margin of error of plus or minus 3 percentage points.
The World Fact Book reports U.S. population at over 300 million, 301,139,947 (estimate as of 2007).

How many people do you think you'd have to poll to get within plus or minus 3% or 300,000 of the correct vote?

10 million? 1 million? This particular CBS pre-poll accurately extrapolates the minds of over 300 million people by polling just 906 people, or .00009 % of the population.


We're not so different after all!